limits and tolerances

[jcnewbie]

I know this is not a Mastercam question but don't know where else to ask.

Can someone tell me how to calcualate the max and min limits of the missing letter in the attached file

Your help is appreciated ?

[Superman]

I would think that is a redundant value, it is what it ends up to be.
it should be the calculated value, with the general drawing tolerance applied.

Dimensioning a drawing is critical, it should be reflected in what it fits onto.
for example, the size between the holes should have the tolerance because the mating part has 2 pins for location, and the distance to the first hole may be not toleranved.

[Mike Mattera]

Is this for a design/engineering class? I agree with Superman, I just doesn't matter. Especially if your running it on a CNC it should all come ont within +/- .001" anyway even on a piece of crap machine.

Besides, the engineer doesn't care about the hole to hole tolerance or you'd have 1.000 +/- .010 as the dimension. No one should be dimensioning the same location from 2 different reference points.

The way it's dimensioned tells you what's important. The position of the hole from the end of the block, is more important than the Hole To Hole position.

Mike Mattera

[jcnewbie]

see info above

[jcnewbie]

This is one of the exercices in a book I found and thought it was quite interesting in finding a solution. As to your question is it for engineering / design. I'm thinking whoever designs this part would want to machine it as well.

So the question from the book is indicate the MAX and MIN Limit value for R.

So based from both of your responses and If I read it correctly.

Max Limit for R = 1
Min Limit for R = 1

Therefore total tolerance = 0.00.

Am I correct ?

[Superman]

Looked at it again
and I think the question asked may be incorrect.

You should have been asked " What is the possible MIN/MAX size of R ?"

then 1st example
1.76-0.74 = 1.020" = max size
1.74-0.76 = 0.980" = min size

[Mike Mattera]

Superman: Much better question. Actually has possible solutions.

Mike Mattera

[jcnewbie]

Thank you !